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Kp Break Charge


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#1 Pretty green flames

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Posted 14 March 2008 - 12:59 PM

Greets

So, I know the formula for normal KP is:

Potassium Perchlorate 70
Charcoal Airfloat 18
Sulfur 12
Dextrin 5

And the one without sulfur is

Potassium perchlorate 70
Charcoal 30
+5% Dextrine

Now, does anyone have any experience with either of the two? There is very little information on the net regarding these two so I was hoping anyone here could shed some light on the sensititivty, power and preparation (Screen and granulate/coat rice hulls?)

Thanks for any information.

#2 pyrotrev

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Posted 14 March 2008 - 01:32 PM

Shimizu covers both in some detail I seem to recall, and makes the point that both are safe (no accidents reported). From memory, KP is almost as powerful as H3, but much slower burning, so use in larger shells or add extra pasting. It's prepared from finely ground ingredients made into a slurry and coated on to rices hulls etc.
Trying to do something very beautiful but very dangerous very safely....

#3 Pretty green flames

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Posted 14 March 2008 - 01:48 PM

I see, so I guess if I used this in a 3" shell I'd have to paste the hell out of it. Does anyone have any practical experience with this break charge, especially in smaller shells (3-4")?

Thanks

#4 maxman

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Posted 14 March 2008 - 01:56 PM

KP is for paper shells, not reccomended for plastic. See Passfire.com

#5 karlfoxman

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Posted 14 March 2008 - 03:38 PM

I have used KP in a 6" paper shell and it broke very well. I ball milled the sulpur and charcoal for 3 hours then screened in the Potassium Perchlorate and SGRS, this was then added to rice crispies to make the charge. I think the power of the burst depends on the pressure, so a harder break is controlled by adding more layers. My 6" had 15 layers and the burst to carrier 3:1. I would recommend using it for larger shells 4-6 inch, and for center of saturn / double petal shells. If your making smaller shells you will need booster or H3 to break them well. But give it a go, Im no expert on ball shells.

This shell used the KP charge, it was a shell of shells.

Ill post the video in Youtube

http://karlfoxman.fr...06/DSC00050.JPG

Edited by karlfoxman, 14 March 2008 - 03:42 PM.


#6 Pretty green flames

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Posted 14 March 2008 - 04:15 PM

Thanks for the information guys, I'll make some shells this weekend and hopefully fire them the next. I'll just use straight granulated KP in them so I'll get more of it inside the shell, the shells will be 3". Hopefully they will turn out OK, better than straight BP anyway.

#7 karlfoxman

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Posted 14 March 2008 - 04:17 PM

Yeah sounds ok, granulating will be better. Remember the key im sure is to add more layers of pasted paper.

#8 maxman

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Posted 14 March 2008 - 04:51 PM

Thanks for the information guys, I'll make some shells this weekend and hopefully fire them the next. I'll just use straight granulated KP in them so I'll get more of it inside the shell, the shells will be 3". Hopefully they will turn out OK, better than straight BP anyway.


Are they paper shells then?Seems a bit of a waste of perc otherwise when whistle or flash will do. Or are you doing it to to see how it works?

#9 Pretty green flames

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Posted 14 March 2008 - 05:10 PM

Are they paper shells then?Seems a bit of a waste of perc otherwise when whistle or flash will do. Or are you doing it to to see how it works?


They are plastic shells (I know). But I'm going to try KP to satisfy my quriosity, see how something else than regular black powder works. To me, this doesn't seem a terrible waste of perc to be honest, besides, I'm more into streamer type stars which, for now, are quite satisfactory, also, they don't any perc. I've had that kilo of perc sitting on the shelf for over a year now and it's time I made something with it :)

#10 karlfoxman

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Posted 15 March 2008 - 09:45 AM

I have uploaded the video of my 6" shell of shells to Youtube now http://uk.youtube.co...h?v=se52cadpO94

#11 Pretty green flames

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Posted 15 March 2008 - 01:54 PM

Looks good, seems like it broke quite well.

I have another question though, have you ever used KP in any of your canister shells? Would additional spiking be needed to make the case sufficiently strong for the KP to take effect?

Thanks for your help

#12 karlfoxman

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Posted 15 March 2008 - 02:50 PM

I have never used KP for my cylinder shells, you dont need to use KP for those, BP is fine for the job and so I would not change that. If you were to use it I would think it would need to be spiked in the same manner that my Maltese cylinders are spiked. For those I use fairly slow BP, its ballmilled for about 2 hours, this would be the burst and its granulated quite fine without binder in some of my shells. Even my rough powder can make an impressive burst its all down to the confinement.

I wouldnt mine seeing some sort of compare test between BP:KP type bursts, maybe you could make some test and get a visual measure of the powder of each break.

#13 MDH

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Posted 15 March 2008 - 10:45 PM

Yeah. A flash booster sounds like a significantly better idea to me. for a 1 or 2" shell you'd only need around half a gram to accelerate the burst and the strength.

#14 Mumbles

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Posted 02 April 2008 - 01:59 AM

I use KP and related compositions for bursting most of my shells. It's been my experience that KP on rice hulls works pretty well from 3" to 6". 6" starts to push it, but for double petals it is good. I used to use it to break canister shells as well would pretty good success. I used a slightly oversized canule and broke them with KP on hulls. I've since changed to a more traditional granulated BP break in canisters, but still use KP on hulls to break comet shells and such. Besides the over sized canule, nothing is done differently. I used a 1" canule in 3" shells, 1 3/8" in 4" shells, and 1 5/8" in 5" shells.

I've also been using another related burst from shimizu. It's the second composition you listed with +5% additional potassium dichromate. It seems to break pretty good. I've heard the composition with just the perc and charcoal recommended for nothing smaller than 10" single breaks. This came from a guy who really likes hard breaks, so take the advice accordingly. I've yet to make anything this large, so it is hard to really comment.

#15 Gazza

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Posted 21 May 2008 - 09:08 AM

I tend to use H3 (sulphurless potassium chlorate/willow charcoal) or Al/perch flash for my smaller shells (1-3inch).
For medium shells, I use H3, KP on rice hulls or BP on rice hulls with a small amount of flash 'booster', depending on the strength of break that I desire to achieve.
For my 8-12 inch shells, I use BP on rice hulls or KP on rice hulls, with optional flash 'booster'. In my experience, flash booster is not required for a KP/rice hull burst charge.
Go very easy on the flash booster- only a small amount is needed. You'll be barking mad to use any more than 2 grams of flash powder! Unless you want your stars pulverised to dust, or blown blind.
I gonna be testing one of my 10 inch chrysanthemum shells tonight. I can't wait! :rolleyes: I'll treat you all to a video of my shell; hope it's not a dud! :ph34r:

Edited by Gazza, 21 May 2008 - 09:21 AM.





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